The moment you start firing any weapon in EVE at another ship or structure, you'll need to think about resistance. Resistance in EVE is defined as the percentage of your damage that is removed before it is actually applied to the target ship or structure. There are four types of damage done in the game: kinetic, explosive, thermal, and EM. Each ship or structure in the game has a resistance to each of the four types of damage. Most player ships and structures have separate resistances, calculated separately, for their shields, armor, and structure. Most NPC ships and structures have only one set of resistances for all three.
Each type of weapon in EVE Online does between one and three types of the four types of damage. Therefore, to do maximum DPS to your target, you'll want to match the damage type that you are doing to the lowest resistance(s) of the target.
Determining the type of damage that you're doing is very easy: simply do a "Show Info" on the ammunition type that you are firing. Select the Attributes tab. Scroll until you see something like this:
This particular ammunition does 18 HP EM damage and 4 HP thermal damage, therefore the damage potential from this ammo is 82% EM, 18% thermal. In some cases, the game will directly tell you the resistances of your target, for instance with this Amarr Control Tower:
In this case, the Control Tower (POS) has zero percent resistance to both EM and thermal, therefore the type of ammunition I chose is a good selection for attacking this particular target. Had I chosen an ammo with a 18 HP explosive damage instead, that explosive damage would be cut by 50% before being applied to the POS. That's resistance.
When attacking NPCs, each type of NPC has a set resistance to two types of damage. You see this quite often in this sort of chart which lots of people post in their EVE biographies:
Angel Cartel: Explosive/KineticIn the case of NPCs, you should both set your resistances to strongly resist the types of damage listed, and should also do damage based on those types. For instance, if fighting Serpentis NPCs, you should both resist against kinetic and thermal damage and should do kinetic and thermal damage yourself.
Blood Raiders: EM/Thermal
Mordu's Legion: Kinetic/EM
Still, these are general statements. Each type of NPC has very specific resistance profile and though they aren't provided in-game, there are ample locations where you can reference them. I personally am a big fan of Chruker's website for this. These tables are particularly helpful for attacking rogue drone NPCs, which are not consistent in the types of damage they have the lowest resistance to.
Using resistances yourself, you'll want to protect your shields or your armor against the specific types of damage being done to you. If you are attacking NPCs, then the type of damage being done will be easy to determine using the data above. During late 2011 and all of 2012, CCP went a long way toward renaming the various types of resistance modules so that it's much easier to find the proper module for the type of tanking you want to do. Both armor and shield ships also have modules that protects against all four types of damage (the Adaptive Nano Plating and Energized Adaptive Nano Membranes for armor, the Adaptive Invulnerability Field for shields), though less efficiently than dedicated resistance modules against a specific type of damage. These modules are referred to in game as "hardeners." "Active hardeners" are those that consume capacitor to function. "Passive hardeners" are ones that do not. Variations of both exist for both shield- and armor-tanking.
One other thing to keep in mind: most resistance modules of the same type fitted to a ship grant decreasing resistance to that type of damage. This is a factor with most modules in EVE no matter their function. Diminishing returns takes its toll in these situations. It's therefore usually not particularly useful to fit more than three modules that protect against all four types of damage, or more than two modules that protect against a single type of damage.
Finally, sooner or later, you will wish to attack another EVE player, or withstand an attack from another EVE player yourself. Again, resistance to damage plays its part in this. Because you usually can't predict what type of damage another EVE player will fire at you, virtually all PvP ships in EVE are "omni-tanked": that is, they are built from the ground up with the highest possible resistance to all four types of attacks. Still, each type of ship in EVE has one type of damage that they are naturally vulnerable to. This is called the ship's "resistance hole" and varies based on the race of the ship and whether it's T1 or T2:
|Ship type||Resistance hole||If hole patched|
|T1 shield tank||EM||Thermal|
|T1 armor tank||Explosive||Kinetic|
By following the chart above, you'll have a pretty good idea of the type of damage that's most likely to go over well when attacking another player's ship. Judge them based on their apparent experience, alliance, and potentially their character age. If these things seem to indicate an experienced player, you can usually safely assume that player has patched the most glaring hole in their ship and you should fire damage consistent with their adjusted lowest resistance. If the player attacker seems less experienced, you can sometimes go straight for the resistance hole...
I hope this basic guide to resistance in EVE has been helpful!
Occasionally on Sundays, I will be defining a common EVE term for those who might not have heard it. If you have a suggestion for such a term, please drop it into the comments.